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What’s the Difference Between EPUB, DPS, and PDF?

I saw this question on twitter recently: “What is the fundamental difference between EPUB3 and Adobe DPS?” and I realized that I’ve been asked this a lot recently. For example, we had an EPUB track and a DPS track at The InDesign Conference and a lot of people wrote in to ask which one they should attend. Plus, how are those different than PDF? And what’s the deal with FXL and SWF and other digital formats?

So, in hopes of clearing the air a bit, here’s My Answer:

Document vs. App

Do you want to be a software developer or a publisher? Software developers make apps (or applications, or programs, or whatever you want to call them). Publishers publish documents. Documents are files that can be viewed in a Viewer application.

So, for example, when you create a PDF file you’re making a document that is going to be viewed in Acrobat or Reader or Preview or a Web browser, or some other program. Similarly, when you export an EPUB file, you are making a document.

The great thing about documents is that you can move them around: you can email them, post them on a server, put them in a store for downloads, save them to disk, archive them, and so on. As long as there is a viewer, you can read them on any device: desktop, laptop, web browser, iOS, Android, Linux, or whatever. Even better, you can distribute them without someone else (e.g. Apple) saying it’s okay.

The great thing about apps is that they are software, so they can do things that only software can do: you can sell them in an app store like a game, you can have in-app purchases, you can optimize for native software speed. But apps have to play by app rules: it’s harder to publish them, they run on just one device type (an iOS app cannot run on Android, etc.), you have to get permission from Apple to publish it to the iTunes store, and so on.

But a strange thing has happened over the past few years: there are a lot of apps that look and act like documents; and some apps allow “issues” that are downloaded and read like documents inside the app (for example, monthly magazine subscriptions). Conversely, documents have gained new powers to act like apps. For example, you can put interactivity into a fixed-layout EPUB file (FXL) and some PDF files that make them interactive, like an app.

DPS

If you want to turn your InDesign document into an app, you’ll need special software and a service. Adobe Digital Publishing Suite (DPS) was the first to offer this, and remains the most popular service today. Make no mistake: DPS is not an authoring tool. DPS is, at its heart, an app creation and distribution service. A lot of people tie DPS to InDesign, but that’s just because they’re both from Adobe, and InDesign was the first tool to connect to DPS. You can now use a wide variety of tools and products (even PowerPoint!) to author for DPS.

Adobe does offer some tools that help you add some DPS interactivity to your documents, and to help get your InDesign document into their DPS system, but not all InDesign features are natively supported in DPS at this time.

Behind the scenes, the DPS system converts your documents into actual software apps. A major part of the DPS ecosystem is its analytics system, which provides insight into what people are reading, how long they’re reading it for, what they tapped/clicked, and more. It’s impressive.

Other App Makers

Fortunately, there are also a number of other players in the “InDesign to App” market, including Twixl and Aquafadas. These companies also offer alternative paths to converting InDesign documents to software apps. And, even better, in many cases they’re very competitive, especially for small to mid-sized companies. (Adobe is currently focusing their DPS efforts on “enterprise” customers—national magazines, larger companies who produce interactive sales materials, government agencies, and so on.)

Web Apps and Web Viewers

There’s a middle-ground, hybrid solution which is also very interesting: Web Apps or other HTML5 solutions. For example, you can create a richly interactive experience that works in a Web browser with eDocker or ajarproduction’s in5, both of which convert your InDesign layout to HTML5. Both systems offer a wide variety of options for what to do with those apps/docs.

For example, at this years’ PePcon: The Print + ePublishing Conference, Jerry Silverman showed you could export a document with in5, then use Adobe’s PhoneGap (which is part of a Creative Cloud membership) to quickly and easily convert the HTML5 package into native iOS and an Android apps.

EPUB, PDF, and other Document Formats

While people get so excited about making apps, I argue that making documents is often preferable for most publishers and creative pros. For example, many folks have been incredibly frustrated after spending dozens or hundreds of hours of hard work on an app, when they are rejected by Apple’s app store for being too much like a book. Apple doesn’t want just a little bit of interactivity; they want immersive, app-like experiences! It’s tricky.

Similarly, it’s much harder to create an app than a document. Making the interactivity in InDesign is fun, but when it comes to taking it the next step — getting it into the app store — well, I heard an publishing IT guy recently call the process “brutal.” Of course, if you’re doing a multi-issue app, then you only need to submit the app once (well, until the OS changes and then you typically need to provide updates), and then each “issue” is easier.

But compare that to exporting and distributing a document, such as a PDF file. You choose File > Export. Done.

The problem with PDF files is that interactive features don’t work very well in them on some devices. For example, buttons and videos often don’t work on iPads; and if you don’t have Flash on your computer, even Acrobat can’t manage a lot of the rich media you can put into a PDF (like audio or video).

Fortunately, there’s a new kid on the block: Fixed Layout EPUB (FXL). You can use the newest version of InDesign to make highly interactive FXL files (with hyperlinks, video, buttons, animations, slide shows, and so on), and these FXL files are documents that you can distribute in many ways. You can publish them in Apple’s iBookstore, or sell them or give them away on your own web site… you can make awesome sales slide presentations and put them on your sales staff’s iPads; you can create children’s books and sell them in a variety of stores…

FXL isn’t perfect. It’s still a relatively new format. You can view it on Mac and Windows and iOS and Android, as long as you have modern EPUB3 reader software. For example, Apple’s iBooks, Adobe’s Digital Editions software, Kobo apps, and the Readium Chrome extension, are all free options for reading FXL files. You cannot play it on Kindle because Amazon does not support EPUB (they have their own proprietary format).

How to Learn More

We are in the middle of a publishing revolution and nothing is stable. You can stay current and learn “how to” publish in all these ways at PePcon: The Print + ePublishing Conference. I hope to see you there!

Other links for learning more about DPS and FXL:

David Blatner

David Blatner

David Blatner is the co-founder of the Creative Publishing Network, InDesign Magazine, and the author or co-author of 15 books, including Real World InDesign. His InDesign videos at Lynda.com are among the most watched InDesign training in the world. You can find more about David at 63p.com.
David Blatner

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12 Comments on “What’s the Difference Between EPUB, DPS, and PDF?

  1. I hope you don’t mind but I think this line requires a bit of clarification:”Behind the scenes, the DPS system converts your documents into actual software apps.”

    Actually it converts them to folios which in turn are read by apps. Not a whole lot different from PDFs or EPUB which require some type of application to read them except in the case of DPS those folios are read by a single proprietary app (we’ll leave the content viewer out of this).

    This may be way oversimplified but it’s an important point.

    • Good point, Bob. In fact, I was hoping that Adobe would make the .folio format open so that we could make our own folio files, put them on our own servers, and download them into Folio Reader apps. (My suggestion to Adobe was: Why don’t you make the free Adobe Reader be able to display PDF, EPUB, and Folio! Wouldn’t that be cool?)

      That said, a “single edition” DPS app merges the folio in with the app itself, so that the folio is essentially an app.

      • Good point about SE which is one of the reasons why it gets so much scrutiny by Apple. But it’s effectively a folio baked into an app.

        But I do love your idea of “universal” reader for all formats.

        The .folio format is available for anyone who wants to license it but I don’t see anyone lining up at Adobe’s doors. I suspect it would be a lot harder to accomplish than we’d like to think.

  2. Great writeup, David!

    Regarding the discussion in the comments: It’s not particularly hard to reverse engineer the folio format (even without documentation) either. I was able to make a proof-of-concept that converted a folio to HTML (with working overlays thanks to in5 code). It’s just that the content was less rich that what was in the original InDesign document. Essentially the folio was a series of screenshots.

    I think the lines between apps and documents will continue to blur back and forth, but it’s helpful if everyone reads this post as a starting point. Keith Gilbert’s MAX presentation from this year is also a very helpful primer for this topic: http://max.adobe.com/sessions/max-online/#/video/521

  3. Just to correct some things, Adobe was not the first to come up with a tablet publishing solution. Actually WoodWing’s tools and the ones from Twixl media were released before Adobe opened up DPS to the public, but that’s not important.

    Opening up the .folio format is not the holy grail either I’m afraid. The format is one thing, but you need the technology to render these files on iOS, Android and the web, which is actually the hardest part of the story. Adobe has also put in a whole bunch of restrictions in the license agreement you have to comply to when you want to create your own .folio files which makes it pretty hard to something sensible with it.

    Remember PDF? The file format has been open since the beginning, but everyone had their own rendering engine. This of course led to a whole bunch of problems as each vendor was interpreting the spec in a different way.

    We at Twixl solved this problem in a different way by providing an option to buy the Twixl Reader SDK. This allows people to embed our reader technology in their own apps. Additionally, own .publication format is completely open if someone wants to use a different tool than Adobe InDesign to generate them. If you want, you can even use your own Amazon S3 or Windows Azure Storage account to store them.

    We also offer the option to convert the InDesign .publication export file into a web reader. This is a plain set of HTML files that can be hosted anywhere. This option is available for everyone that has a licensed version of Twixl Publisher.

    In our next major version, we will be adding support for HTML, which is a much more universal format than what .folio, .publication and similar formats are.

  4. David,

    Nice article explaining the differences between EPUB, DPS and PDF. It can be a confusing tangle when you first venture into publishing/app field. Your explanation was concise and to the point and helped clear up some confusion on my part.

  5. Nice write up David.
    I actually did a 3 hour presentation on this 2 weeks ago during a seminar. I think there’s a lot of truth to your comparison but I’m missing a few things here. I also wrote up a few things on my blog
    http://www.bartvdw.com/general/adobe-dps-general/adobe-dropping-dps-single-edition

    Here are a few things I would like to add:
    First of all in the Document vs App comparison I think it’s important to note that one of the main advantages of using “documents” is freedom of distribution. While with most app building services you’re tied to the App Store for distribution. You only have 2 places to put your app, either on the store (publicly) or protected in your own enterprise. You can’t put the app on your own website or anything (because of your terms of service with Apple). And having a public app but with hidden (protected) content requires you to use an expensive direct entitlement server.
    Freedom of distribution is one of the most important questions I want my clients to answer before guiding them towards a specific digital publishing solution.

    Apps, even with publications in them, are treated like apps when it comes to Apple’s approval. This sucks. But it’s Apple that’s allowing you to build a storefront and publish it into Newsstand. Newsstand is built specifically for publishers which is odd since they have the iBookstore too (wasn’t THAT one for publishers??). So because of this Apple wants to attract rich publications into the App Store. So because of Newsstand there is still a need for some publishers to continue as an app and not as an ePub. iBookstore doesn’t offer the Newsstand functionality.

    Last one: business monetisation. Don’t forget that publishing is still about commercial activities. And I hardly hear anyone talk about this side of things. And there’s a big difference between publishing into an app or publishing as PDF / ePub. Using apps you have a whole back-end system with in-issue analytics, push notifications, subscriptions (both standard and with entitlement), offer “first-issue free” options and many other marketing tricks. Because that’s what solutions like DPS are, marketing solutions and not just design solutions. And I’m missing the monetisation opportunities that PDF and ePub offer today. Especially if you’re into periodicals or publications that you with to bundle together. With those formats you’d have to build the back-end IT infrastructure yourself.

    Don’t get me wrong, I’m not only cheering for apps (because they ARE a huge pain to create) but I’m just trying to say that you can’t just compare them as “these are publications” and “these are apps”. I love the ease of use of PDF and ePub, the fact I can place them anywhere I want, most tablets can read them (with a certain reader app), etc. But there’s a specific use case for both type of systems.

  6. The biggest drawback with Fixed Layout ePubs is that the interactivity is limited to clicking around, but there is no way to deal with user input.

    Maybe one day, that may become available…

    • Max: I’m not sure what you mean by “user input.” It can deal with clicking buttons and that kind of input. But if you mean forms (where people input text) then no, that is not available.

  7. David! Thx for linking me to this site and the huge informational input, i got from here. I learned a lot! I wished i read this before i started doing my PressKit. This would have prevented me a lot of pain. Things are clearer now.
    Thanks again.

  8. Hey David, thanks for this clearing those subjects in my mind!
    Could you explain me a little more the differences between a EPUB generated from indd and from a convertion from PDF? I know somethings the convertion is not perfect, but I would like to have more details about it.
    It would be even better if you have material to indicate me.

    Thank you!
    Alexandre.

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